1. Field of the Invention
The present invention relates to an improvement in a perimeter used to test a visual field.
2. Description of the Prior Art
Heretofore, there has been known a perimeter for testing functions of a retina or optic nerves of a subject's eye. In this type of perimeter, a plurality of targets are exhibited to the eye to test so-called kinetic and static visual fields.
In the visual field test, a screening test is first made in order to test the visual fields effectively and in a short time, and then, based on the results of the screening test, testing points are added for precise tests.
However, in this type of conventional perimeter, the testing points are added using, for example, a light pen manually and on operator's intuitional judgment. Therefore, there is a problem in that the testing points cannot be added effectively and in a short time if an operator is unskilled.
A perimeter also has been known in which testing points are automatically added. However, in this conventional perimeter, when a tested value is less than a predetermined value, the tested value is regarded as an isolated defective point, so that testing points are automatically added in the neighborhood of the defective point. For this reason, too many testing points are liable to be added. Further, a case also occurs in which testing points that do not contribute to the actual testing of the visual field are added. Consequently, a useless burden is unfavorably imposed on a subject.